Allostatic load and cardiometabolic health in a young adult South African population: The African-PREDICT study.

Abstract

Sustained stress, assessed as a high allostatic load score (ALS), is an independent cardiovascular disease (CVD) risk factor in older adults but its associations in young people are undefined. Since neurological maturation impacts stress adaptation and CVD risk, we assessed the relationship of ALS with CVD profile using a tiered approach stratified by age (emerging adults 20-24y, EA vs. young adults 25-30y, YA) and ALS (high vs. low). In 1054 healthy African-PREDICT participants, we determined: 1) ALS in EA vs. YA; 2) the relationship between ALS with cardiovascular health; and 3) the odds of high ALS>4 to identify masked hypertension and prediabetes as cardiometabolic outcomes. A 9-component four-domain ALS was compiled: neuro-endocrine (dehydroepiandrosterone, cortisol), inflammatory (interleukin-6, C-reactive protein), cardiovascular (systolic and diastolic-blood pressure), and metabolic (total cholesterol, HDL-cholesterol, body mass index). Retinal vessel caliber, pulse wave velocity (PWV), cardiac structure and function were assessed. Median ALS was 3 (range:1-9). A high-ALS>4 was more common in YA vs. EA (47%vs.35%, P=0.032). Higher ALS associated with narrower retinal arteries (P<0.01), greater PWV (P=<0.01), lower diastolic (P<0.01) and left ventricular function (P<0.01). High-ALS increased the odds of having masked hypertension, prediabetes, narrower retinal arteries, higher LV mass, poorer diastolic and ventricular function (all P≤0.01) in EA and YA independent of traditional CVD risk factors. The composite ALS identified early stress dysregulation in cardiometabolic health and higher odds for prediabetes and masked hypertension in young adults. Cumulative stress may be a modifiable independent cardiometabolic risk factor in younger populations that needs further investigation.